Media Center

MOX Fuel Makes Sense

April 14, 2011

David Jones, Senior VP, Back End Business Group, AREVA North America

Let’s start with this fact: MOX fuel has been used safely for decades in numerous nuclear reactors worldwide.

Now let’s dig into the details.

Most fuel used in nuclear reactors is uranium oxide. Uranium oxide (UOX) is also the primary material in mixed oxide (MOX) fuel. In MOX fuel assemblies, uranium oxide averages between 90- to 97-percent of the mixture, with the remainder being plutonium oxide. Of the total amount of fuel assemblies in a reactor, typically up to 30% can be MOX fuel.


For more than 40 years, AREVA's MOX fuel---now made at the MELOX facility in France---has safely powered nuclear reactors.

The uranium oxide fuel used in most reactors naturally creates plutonium as the fuel powers the reactor, generating up to 1% of plutonium in the used fuel over three years. It is this plutonium that is separated out and recycled into MOX fuel. A nuclear reactor using 30% MOX fuel (containing 3-10% plutonium) consumes as much plutonium as it produces, helping to stabilize inventories of nuclear materials by minimizing the amount of plutonium produced by nuclear power plants.

The Unit 3 reactor at Fukushima contained less than 6% of MOX fuel. It bears mention that MOX fuel assemblies in an operating reactor do not pose an additional threat when compared with traditional uranium oxide fuel assemblies. The melting point of the MOX fuel assemblies is nearly identical to uranium fuel assemblies, so the risk of damage due to overheating does not significantly increase with the use of MOX fuel.

While any release of fissile material is serious, plutonium is a heavy metal that does not disperse easily in air or water, and does not migrate easily through a food chain. For example, of any plutonium amount in the ground, less than one one-thousandth would be absorbed by plant roots. If the plant is consumed, less than one one-thousandth of the amount in the plant would be absorbed.

MOX fuel makes sense. It is an effective recycled material with a demonstrated history of safe, useful service. Five different independent safety authorities in five countries outside the U.S. have analyzed the use of MOX fuel in commercial reactors, including under severe accident conditions, and determined that it is safe and meets the same rigorous licensing standards as UOX fuel.

BTW, with a nod to the President’s energy speech, the energy in one gram of plutonium equals the energy in one ton of oil.

The simultaneous natural disasters in Japan created an immense need for responsive, compassionate care and support from knowledgeable, expert providers. We are responding to that need with supplies, expertise, and clarity to ensure the proper actions have the most immediate impact.